More foul calls on plays moving from right to left

Referees are more likely to make foul calls when they see the action moving from right to left, or leftward, according to a new study by brain researchers at the University of Pennsylvania.

Twelve varsity soccer players were shown identical images of plays, with the only difference being that some viewed the images flipped horizontally, so there were right-to-left and left-to-right versions. The participants that saw the action as moving from right-to-left were statistically more likely to call a foul.

Other studies have shown that the direction in which people read and write leads to a bias toward rightward or leftward action. One study found that Italians were more likely to view a soccer goal as “stronger, faster and more beautiful” when it was presented with a left-to-right trajectory rather than the other way around, and that Arabic speakers showed the opposite bias.

I’m not certain that the studies described really prove the claim — the experiments should be run with actual referees (who may minimize the directional bias by training or practice). In any case, they’re interesting and a valuable reminder of how subtly biases can exist in our perceptions.